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idle won't come under 1000 rpm's after HEI istallation

616 Views 5 Replies 0 Participants Last post by **DONOTDELETE**, Dec 9, 1999

Discussion Starter · Dec 7, 1999

idle won\'t come under 1000 rpm\'s after HEI istallation

1)-I just finished my HEI installation (+ nutter by-pass)on my 87 yj. It runs a lot smoother than before, however it runs at 1100 rpm. I tried adjusting the idle rev with the linkages at the carb but won't go under 1100 or 1000 with A/C on.

what can i do to lower RPM's to +/- 700?

2)- i got rid of most sensors and vacums, but don't know which is the best vacuum source for the HEI. I have a BDD rebuilt by Holley with two vacuums, one in fornt of carb other in back. Which should i use?

3)- I also have the crane vacuum adjusting kit? will this help? Should i change the weights or just play with springs? Ssshould i go softer springs or harder springs?

Thanks in advance for replys.

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Discussion Starter · #2 · Dec 7, 1999

Re: idle won\'t come under 1000 rpm\'s after HEI istallation

Perhaps you installed the distributor with it off a tooth, thus the timing might be way advanced. If the timing is way advanced, your idle will go up. Sounds like this could be the possible cause to me.

Marc
Contagious Off-Road

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Discussion Starter · #3 · Dec 8, 1999

Re: idle won\'t come under 1000 rpm\'s after HEI istallation

Start looking for vacuum leaks. One mistake was to take off any of the emissions controls. They don't hurt performance, they are there to improve the running...for example...there is a solenoid between manifold vacuum and the PCV. At idle it energizes to block the PCV, thus lowering the idle. If this is removed then that is part of your problem. Vacuum leaks are one of the biggest problems with the 258. You can use a combination of carb cleaner and pinching vacuum hoses to see which one causes the idle to drop (carb cleaner will cause a momentary increase).

Take your time and go through all the sub-systems. Good Luck.

John......southern CA
84CJ7,3"lift,32"BFG,4.11's,ARB,Solid Axle's

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Discussion Starter · #4 · Dec 9, 1999

Re: won\'t idle under 1000 rpm\'s after HEI - please more info to finalise setup.

Thanks for replys, I will check all subsystems this weekend, however nobody has answered the question on the best source of vacume for the HEI. I've heard, ported or manifold. I can't find any source of manifold vacume in my 87yj and two on my carter BBD. Which is better? I plan to work on it this weekend and will like some help.
Although timing is OK and power is OK, the jeep coughs when hitting the gas after decelerating (like when slowing down in a sharp corner, or running stop sign). Is this a problem with the advance springs?

Please help

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Discussion Starter · #5 · Dec 9, 1999

Re: won\'t idle under 1000 rpm\'s after HEI - please more info to finalise setup.

Ported may be better but this is one of those things where no one answer is right for everyone. Try em both!

Your problem are starting to sound related to something other than the ignition.

LarryM
85 CJ7, 350TBI ,T19 4spd
'00 TJ Sport, NV3550 5spd, D44, Teraflex system

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Discussion Starter · #6 · Dec 9, 1999

Re: won\'t idle under 1000 rpm\'s after HEI - please more info to finalise setup.

Where/how do i find the ported vacum? I see two sources in the carb. Is "ported vacume" in the carb? front or rear?

Sorry for my ignorance but I am still in the learning curve.

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